1. Field of the Invention
The present invention relates generally to thin-film recording heads for use in, for example, floating magnetic heads. In particular, it relates to a thin-film magnetic head in which an electrical connection between first coil segments and second coil segments can be easily and reliably formed and in which the second coil segments are properly insulated from a magnetic pole layer.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication Nos. 11-273028, 2000-311311, and 2002-170205 and U.S. Pat. No. 6,335,846 B1 teach inductive recording heads each having a coil layer including a coil toroidally wound around a core.
The coil is preferably toroidal to best utilize the three-dimensional space near the core layer. This structure has been expected to achieve miniaturization of inductive heads and superior magnetic efficiency.
In all the above-described prior art documents, a lower coil layer, which is formed below the core layer, e.g., an upper magnetic pole layer, is electrically connected to an upper coil layer, which is formed above the core layer, via connectors.
For example, Japanese Unexamined Patent Application Publication Nos. 2000-311311 and 2002-17020 teach a structure including through holes each formed across a first insulating layer covering a lower coil layer and each side portion of a second insulating layer extending over the core layer in the track width direction. A connector is formed in each through hole so that the upper face of the connector comes into contact with a side portion of the upper coil layer. Although the above-described patent documents do not include front views of the lower coil layer, the upper coil layer, and the connectors viewed from the face opposing the recording medium (hereinafter referred to as “opposing face”), it can be inferred from the description that the front view is such as that shown in FIG. 20.
As shown in FIG. 20, step differences are formed between the upper face of the core layer and the upper face of the first insulating layer. As a result, step differences are formed in the second insulating layer extending over the core layer. The presence of the step differences degrades the accuracy of patterning in forming the upper coil layer. In particular, the patterned resist formed on the connector is not accurately removed, thereby causing connection failure between the connector and the side portion of the upper coil layer formed in the pattern by plating.
Moreover, in forming the second insulating layer, the material does not readily deposit on the side faces of the core layer due to the step differences. As a result, insulation between each side face of the core layer and the upper coil layer becomes incomplete. The easiest way to overcome these problems is to increase the thickness of the second insulating layer. However, since the total thickness of the first and second insulating layers increases, forming through holes that extend across the first and second insulating layers to come into contact with the upper face of the lower coil layer becomes difficult. As a result, the electrical connection between the lower coil layer and the connectors becomes instable.